In order to improve the results of allografts in the area of the knee in humans and animals, isolated parameters will be studied in a sequential fashion. In particular, the immune response and storage techniques will be studied with respect to their harmful effects on the graft, and attention will be paid to prevention of these harmful effects. Three models are being studied. The first is the rat distal femur allograft model which will be used primarily for the study of the immune response and its prevention. It will also be used to determine optimal techniques for storage. The medial knee dog shell allograft model will be used to determine whether or not improvement occurs with inhibition of the immune response. A vascularized total knee joint model in the cat will be studied to determine whether immune inhibition can maintain vascular patency.